Ultrasonic transducer, ultrasonic probe, diagnostic device, and electronic instrument

ABSTRACT

An ultrasonic transducer includes “m” first ultrasonic elements including first diaphragms, and “n” second ultrasonic elements including second diaphragms. “m” represents a number of the first ultrasonic elements and is an integer of 1 or more. Each of the first diaphragms has a first area. “n” second ultrasonic elements includes second diaphragms. Each of the “n” second diaphragms has a second area being smaller than the first area. “n” represents a number of the second ultrasonic elements and is an integer larger than “m”. The “m” first ultrasonic elements are electrically connected in series in a case where “m” is an integer of 2 or more. The “n” second ultrasonic elements are electrically connected in series. B/A is within a range of 0.9 to 1.1, when a total sum of the first areas is “A” and a total sum of the second areas is “B”.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. patentapplication Ser. No. 13/896,719, filed on May 17, 2013. This applicationclaims priority to Japanese Patent Application No. 2012-115321 filed onMay 21, 2012. The entire disclosures of U.S. patent application Ser. No.13/896,719 and Japanese Patent Application No. 2012-115321 are expresslyincorporated by reference herein.

BACKGROUND

Technical Field

The present invention relates to an ultrasonic transducer, an ultrasonicprobe, a diagnostic device, and an electronic instrument.

Background Technology

An ultrasonic transducer in which a plurality of ultrasonic elements arearranged in a matrix pattern has been known. This ultrasonic transducerincludes a substrate that has a plurality of openings, a supporting filmthat is provided on the substrate so as to cover each of the openings,and a piezoelectric element that is provided on a part of the supportingfilm corresponding to each of the openings. A diaphragm is constructedby the part of the supporting film corresponding to the opening which isa part coinciding with the opening of the supporting film in a planarview. The ultrasonic element is constructed by the diaphragm and thepiezoelectric element provided on the diaphragm.

In this ultrasonic transducer, it has been known that two kinds ofultrasonic elements in which the areas of the diaphragms are differentare provided, and are driven at different frequencies (for example, seePatent Document 1). In Patent Document 1, it is considered that theplurality of ultrasonic elements having the larger areas of thediaphragms are electrically connected in parallel with respect to eachother. Likewise, it is considered that the plurality of ultrasonicelements having the smaller areas of the diaphragms are electricallyconnected in parallel with respect to each other.

When the two kinds of ultrasonic elements are compared, since theultrasonic elements having the larger areas of the diaphragms have lowresonance frequency, they are driven at low frequency and generateultrasonic waves of low frequency. Also, since the ultrasonic elementshaving the smaller areas of the diaphragms have high resonancefrequency, they are driven at high frequency and generate ultrasonicwaves of high frequency. In a diagnostic device having an ultrasonicprobe that uses this ultrasonic transducer, when a deep part (longdistance) of a living body as a test target is diagnosed, ultrasonicwaves of low frequency are used for diagnosis because ultrasonic wavesof high frequency cannot reach a deep part. On the other hand, when ashallow part (short distance) of a living body is diagnosed, ultrasonicwaves of high frequency are used for diagnosis so as to increase theresolution.

However, the sensitivity of an ultrasonic element becomes high as thearea of the diaphragm becomes large. Therefore, the well-knownultrasonic transducer has a problem that the sensitivity of theultrasonic elements having the smaller areas of the diaphragms is lowerthan that of the ultrasonic elements having the larger areas of thediaphragms. Further, due to the difference in the sensitivity, there isa problem that the magnitude of a signal output from each ultrasonicelement is different, and a circuit configuration becomes complicated inorder to match the magnitude of the signal.

Japanese Laid-open Patent Publication No. 2006-75425 (Patent Document 1)is an example of the related art.

SUMMARY Problems to be Solved by the Invention

The advantage of the invention is to provide an ultrasonic transducer,an ultrasonic probe, a diagnostic device, and an electronic instrumentin which the difference in the sensitivity between two kinds ofultrasonic element groups is reduced, ultrasonic waves of a plurality offrequencies can be transmitted and received, and also the circuitconfiguration can be simplified.

Means Used to Solve the Above-Mentioned Problems

This advantage is achieved by the invention described below. Accordingto one aspect of the invention, an ultrasonic transducer of theinvention includes “m” first ultrasonic elements and “n” secondultrasonic elements. The “m” first ultrasonic elements includes firstdiaphragms. The “m” first ultrasonic elements are configured andarranged to transmit and receive ultrasonic waves, where “m” representsa number of the first ultrasonic elements and is an integer of 1 ormore. Each of the first diaphragms having a first area. The “n” secondultrasonic elements include second diaphragms. Each of the “n” seconddiaphragms has a second area being smaller than the first area. The “n”second ultrasonic elements are configured and arranged to transmit andreceive the ultrasonic waves, where “n” represents a number of thesecond ultrasonic elements and is an integer larger than “m”. The “m”first ultrasonic elements are electrically connected in series in a casewhere “m” is an integer of 2 or more. The “n” second ultrasonic elementsare electrically connected in series. B/A is within a range of 0.9 to1.1, when a total sum of the first areas is “A” and a total sum of thesecond areas is “B”.

BRIEF DESCRIPTION OF THE DRAWINGS

Referring now to the attached drawings which form a part of thisoriginal disclosure:

FIG. 1 is a perspective view showing an embodiment of an ultrasonicprobe according to the invention;

FIG. 2 is a plan view showing an ultrasonic transducer of the ultrasonicprobe shown in FIG. 1;

FIG. 3 is a plan view showing a cell unit of the ultrasonic transducershown in FIG. 2;

FIG. 4 is a plan view enlarging a part of the ultrasonic transducershown in FIG. 2;

FIG. 5 is a sectional view along line A-A of FIG. 4;

FIG. 6 is a perspective view showing an embodiment of a diagnosticdevice according to the invention; and

FIG. 7 is a block diagram showing the embodiment of the diagnosticdevice according to the invention.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Hereinafter, the ultrasonic transducer, the ultrasonic probe, thediagnostic device, and the electronic instrument of the invention willbe explained in detail based on a preferred embodiment shown in theattached drawings.

Embodiment of Ultrasonic Transducer and Ultrasonic Probe

FIG. 1 is a perspective view showing an embodiment of the ultrasonicprobe according to the invention. FIG. 2 is a plan view showing theultrasonic transducer of the ultrasonic probe shown in FIG. 1. FIG. 3 isa plan view showing a cell unit of the ultrasonic transducer shown inFIG. 2. FIG. 4 is a plan view enlarging a part of the ultrasonictransducer shown in FIG. 2. FIG. 5 is a sectional view along line A-A ofFIG. 4.

Hereinafter, explanations will be made by describing the upper side inFIG. 2-FIG. 5 as “upper”, the lower side as “lower”, the right side as“right”, and the left side as “left”. In FIG. 2 and FIG. 3,illustrations of parts and the like of an acoustic matching section, anupper electrode, a lower electrode, a conducting wire for an upperelectrode, and a conducting wire for a lower electrode are omitted, andthe ultrasonic transducer is schematically illustrated. Further, in FIG.2 and FIG. 3, the outline of the cell unit is shown by a broken line. InFIG. 4, an illustration of the acoustic matching section is omitted.Also, as shown in each drawing, an X axis and a Y axis orthogonal toeach other are assumed. An X axis direction corresponds to an azimuthdirection, and a Y axis direction corresponds to a slice direction.

As shown in FIG. 1, an ultrasonic probe 10 has a case 200, and anultrasonic transducer 1 that is housed (accommodated) in the case 200.The ultrasonic transducer 1 is disposed in a tip end portion (the lowerside in the drawing) of the case 200. In such a case, a substrate 2,described below, of the ultrasonic transducer 1 is fixed to the case 200directly or with a supporting member for supporting the substrate 2. Thesupporting member is not shown in the drawing. The ultrasonic probe 10can be used as an ultrasonic probe for various kinds of diagnosticdevices such as a diagnostic device 100 described below.

In the present embodiment, a surface of the ultrasonic transducer 1,that is, a surface of an acoustic matching section 6 is exposed outside.The acoustic matching section 6 serves as a protective layer of theultrasonic probe 10 and the ultrasonic transducer 1. Although theconstituent material of the acoustic matching section 6 is not limitedto a specific one, a material that is substantially similar to a livingbody with respect to the acoustic impedance, such as silicone rubber, isused. Here, it may be configured such that the surface of the acousticmatching section 6 is not exposed outside.

In the present embodiment, the ultrasonic probe 10 is a contact typesensor that is used by bringing the surface of the acoustic matchingsection 6 into contact with (applying to) a living body as a testtarget. Specifically, in conducting a test, the ultrasonic probe 10 isused by applying the surface of the acoustic matching section 6 to aliving body as a test target. In such a case, when ultrasonic waves aresent out from an ultrasonic element, described below, of the ultrasonictransducer 1 toward the acoustic matching section 6, the ultrasonicwaves pass through the acoustic matching section 6 and propagate throughthe living body. Then, the ultrasonic waves reflected on a predeterminedpart inside the living body pass through the acoustic matching section 6and are input to the ultrasonic element.

Also, the ultrasonic probe 10 is electrically connected with a devicemain body 300 (see FIG. 6 and FIG. 7), described below, of thediagnostic device 100 through a cable 210. As shown in FIG. 2-FIG. 5,the ultrasonic transducer 1 has the substrate 2, a plurality of (nine inthe configuration shown in the drawing) cell units (ultrasonic elementunits) 4 that are provided on the substrate 2 so as to transmit andreceive ultrasonic waves, and the acoustic matching section 6 that isprovided on the substrate 2 on the side of the cell units 4 so as tocover each of the cell units 4.

Although the shape of the substrate 2 is not limited to a specific one,it forms a quadrangle in a planar view (in a planar view seen from thethickness direction of the substrate 2) in the configuration shown inthe drawing. Also, as another shape of the substrate 2 in a planar view,another polygon such as a pentagon or a hexagon, a circle, or an ellipsecan be listed, for example. Although the constituent material of thesubstrate 2 is not limited to a specific one, a material for forming asemiconductor such as silicon (Si) is used, for example. Consequently,it can be processed easily by etching or the like. Each cell unit 4 isarranged on the substrate 2 in a matrix pattern, that is, in atwo-dimensionally pattern with predetermined intervals. In other words,a plurality of (three in the configuration shown in the drawing) cellunits 4 are arranged in parallel along the X axis direction, and aplurality of (three in the configuration shown in the drawing) cellunits 4 are arranged in parallel along the Y axis direction.

The cell unit 4 has a first ultrasonic element group 3 a provided with“m” first ultrasonic elements (first ultrasonic vibrators) 8 a, with “m”representing the number of the first ultrasonic elements and being aninteger of 1 or more (one in the configuration shown in the drawing),that have first diaphragms 51 a, and transmit and receive ultrasonicwaves, a second ultrasonic element group 3 b provided with “n” secondultrasonic elements (second ultrasonic vibrators) 8 b, with “n”representing the number of the second ultrasonic elements and being aninteger larger than “m” (four in the configuration shown in thedrawing), that have second diaphragms 51 b whose areas (areas in aplanar view) are smaller than those of the first diaphragms 51 a, andtransmit and receive ultrasonic waves, and two third ultrasonic elementgroups 3 c and 3 d provided with “k” third ultrasonic elements (thirdultrasonic vibrators) 8 c, 8 d, with “k” representing the number of thethird ultrasonic elements and being an integer larger than “m” (nine inthe configuration shown in the drawing), that have third diaphragms 51 cand 51 d whose areas (areas in a planar view) are smaller than those ofthe second diaphragms 51 b, respectively, and transmit and receiveultrasonic waves. However, the number of the third ultrasonic elementgroups may be one.

Hereinafter, the first ultrasonic element group 3 a, the secondultrasonic element group 3 b, and the third ultrasonic element groups 3c and 3 d are also referred to as “ultrasonic element group”,respectively. Further, the first ultrasonic element 8 a, the secondultrasonic element 8 b, and the third ultrasonic elements 8 c and 8 dare also referred to as “ultrasonic element”, respectively. Further, thefirst diaphragm 51 a, the second diaphragm 51 b, and the thirddiaphragms 51 c and 51 d are also referred to as “diaphragm”,respectively.

The first ultrasonic element group 3 a is disposed at the upper left,the second ultrasonic element group 3 b is disposed at the lower right,the third ultrasonic element group 3 c is disposed at the upper right,and the third ultrasonic element group 3 d is disposed at the lowerleft, respectively. However, needless to say, the invention is notlimited to this arrangement. Here, explanations will be made on thefirst ultrasonic element 8 a, the second ultrasonic element 8 b, and thethird ultrasonic elements 8 c and 8 d. However, these ultrasonicelements 8 a, 8 b, 8 c, and 8 d have similar basic configurationsalthough the sizes are different. Hereinafter, therefore, explanationswill be made on the first ultrasonic element 8 a as a representative. InFIG. 4 and FIG. 5, for the second ultrasonic element group 3 b and thethird ultrasonic element groups 3 c and 3 d, each section thereof thatcorresponds to each section of the first ultrasonic element group 3 a isshown with a reference symbol “b”, “c” or “d” instead of “a” at the endthereof with parenthesis.

As shown in FIG. 4 and FIG. 5, the first ultrasonic element 8 a isconstructed by the first diaphragm 51 a and a piezoelectric body(piezoelectric element) 7 a. The first ultrasonic element 8 a is formedon the substrate 2. Although the shape of the piezoelectric body 7 a isnot limited to a specific one, it forms a circle in a planar view in theconfiguration shown in the drawing. Also, as another shape of thepiezoelectric body 7 a in a planar view, a quadrangle (square,rectangle), a polygon such as a pentagon or a hexagon, or an ellipse canbe listed, for example. Incidentally, the piezoelectric body 7 a and thewiring thereof will be described below. An opening 21 for forming thefirst diaphragm 51 a of the first ultrasonic element 8 a is formed in apart of the substrate 2 corresponding to each of the first ultrasonicelement 8 a. Although the shape of the opening 21 is not limited to aspecific one, it forms a circle in a planar view in the configurationshown in the drawing. Also, as another shape of the opening 21 in aplanar view, a quadrangle (square, rectangle), a polygon such as apentagon or a hexagon, or an ellipse can be listed, for example.

A supporting film 5 is formed on the substrate 2, and each of theopenings 21 is covered with the supporting film 5. The first diaphragm51 a is constructed by a part of the supporting film 5 corresponding tothe opening which is a part (region) covering the opening 21, that is, apart coinciding with (part overlapping with) the opening 21 of thesupporting film 5 in a planar view. The piezoelectric body 7 a isprovided on the first diaphragm 51 a.

Although the constituent material of the supporting film 5 is notlimited to a specific one, the supporting film 5 is constructed by alayered body (two-layer structure) of an SiO₂ layer and a ZrO₂ layer, oran SiO₂ layer, for example. In a case where the substrate 2 is an Sisubstrate, the SiO₂ layer can be formed by conducting a thermaloxidation treatment to the surface of the substrate 2. The ZrO₂ layercan be formed on the SiO₂ layer, for example, by a technique such assputtering. Here, the ZrO₂ layer is a layer for preventing Pb thatconstitutes PZT from diffusing into the SiO₂ layer when PZT is used as apiezoelectric film 72 a of the piezoelectric body 7 a, for example. Thepiezoelectric film 72 a of the piezoelectric body 7 a will be describedbelow. The ZrO₂ layer also has an effect such as an effect of improvingdeflection efficiency with respect to deformation of the piezoelectricfilm 72 a.

As shown in FIG. 5, the piezoelectric body 7 a has a lower electrode 71a formed on the first diaphragm 51 a (the supporting film 5), thepiezoelectric film 72 a formed on the lower electrode 71 a, and an upperelectrode 73 a formed on the piezoelectric film 72 a. Also, a conductingwire (wiring) for a lower electrode 711 a is connected with the lowerelectrode 71 a, and the conducting wire for a lower electrode 711 aextends along the Y axis direction on the supporting film 5 as shown inFIG. 4, for example. The conducting wire for a lower electrode 711 a iselectrically connected with the cable 210 via a through-hole formed inthe supporting film 5 and the substrate 2. The through-hole is not shownin the drawing. With this configuration, the first ultrasonic element 8a (the first ultrasonic element group 3 a) can be driven independently.Likewise, the second ultrasonic element group 3 b and the thirdultrasonic element groups 3 c and 3 d can be driven independently.

In the second ultrasonic element group 3 b, each second ultrasonicelement 8 b is electrically connected in series by a conducting wire fora lower electrode 711 b. In this case, the conducting wire for a lowerelectrode 711 b is interposed between lower electrodes 71 b of twoadjacent second ultrasonic elements 8 b, and the lower electrodes 71 bof the two adjacent second ultrasonic elements 8 b are electricallyconnected by the conducting wire for a lower electrode 711 b.

Likewise, in the third ultrasonic element group 3 c, each thirdultrasonic element 8 c is electrically connected in series by aconducting wire for a lower electrode 711 c. In this case, theconducting wire for a lower electrode 711 c is interposed between lowerelectrodes 71 c of two adjacent third ultrasonic elements 8 c, and thelower electrodes 71 c of the two adjacent third ultrasonic elements 8 care electrically connected by the conducting wire for a lower electrode711 c.

Likewise, in the third ultrasonic element group 3 d, each thirdultrasonic element 8 d is electrically connected in series by aconducting wire for a lower electrode 711 d. In this case, theconducting wire for a lower electrode 711 d is interposed between lowerelectrodes 71 d of two adjacent third ultrasonic elements 8 d, and thelower electrodes 71 d of the two adjacent third ultrasonic elements 8 dare electrically connected by the conducting wire for a lower electrode711 d.

As shown in FIG. 4 and FIG. 5, for example, a conducting wire (wiring)for an upper electrode 731 a is connected with the upper electrodes 73a, 73 b, 73 c and 73 d, and the conducting wire for an upper electrode731 a extends along the X axis direction on the supporting film 5. Theconducting wire for an upper electrode 731 a serves as a commonconducting wire of each first ultrasonic element 8 a (the firstultrasonic element group 3 a), the second ultrasonic element group 3 b,the third ultrasonic element group 3 c, and the third ultrasonic elementgroup 3 d arranged in the X axis direction, and is connected to the GND,for example, at the end portion thereof. In this manner, the upperelectrodes 73 a, 73 b, 73 c and 73 d of the ultrasonic element 8 a, 8 b,8 c and 8 d are earthed. Alternatively, contrary to the above, theconducting wires for a lower electrode 711 a, 711 b, 711 c, and 711 dmay be connected to the GND.

The constituent materials of the lower electrode 71 a, the upperelectrode 73 a, the conducting wire for a lower electrode 711 a, and theconducting wire for an upper electrode 731 a are not limited to specificones as long as they have conductive properties, respectively. Forexample, various kinds of metal materials can be used. Also, the lowerelectrode 71 a, the upper electrode 73 a, the conducting wire for alower electrode 711 a, and the conducting wire for an upper electrode731 a may be single layers, respectively, or may be layered bodies inwhich a plurality of layers are laminated, respectively. As specificexamples, for example, a Ti/Ir/Pt/Ti layered film can be used as thelower electrode 71 a and the conducting wire for a lower electrode 711a, respectively, and an Ir film can be used as the upper electrode 73 aand the conducting wire for an upper electrode 731 a, respectively.

The piezoelectric film 72 a is made by forming PZT (lead zirconatetitanate) into a film shape, for example. In the present embodiment, PZTis used as the piezoelectric film 72 a. However, any material can beused as long as it is a material that can contract (expand or contract)in an in-plane direction by applying a voltage thereto. For example,lead titanate (PbTiO₃), lead zirconate (PbZrO₃), lead lanthanum titanate((Pb, La) TiO₃), or the like can be used as well as PZT.

In the first ultrasonic element 8 a, for example, when a voltage isapplied between the lower electrode 71 a and the upper electrode 73 a bythe device main body 300 (see FIG. 6, FIG. 7) through the cable 210, thepiezoelectric film 72 a expands or contracts in the in-plane direction.In this instance, a surface of the piezoelectric film 72 a is attachedto the supporting film 5 through the lower electrode 71 a, and the upperelectrode 73 a is formed on the other surface thereof. Here, since anyother layer is not formed on the upper electrode 73 a, the supportingfilm 5 side of the piezoelectric film 72 a does not easily expand orcontract, while the upper electrode 73 a side of the piezoelectric film72 a easily expands or contracts. Therefore, when a voltage is appliedto the piezoelectric film 72 a, deflection that causes projection occurson the opening 21 side, which results in deflection of the firstdiaphragm 51 a. Consequently, when an alternating voltage is applied tothe piezoelectric film 72 a, the first diaphragm 51 a vibrates withrespect to the film thickness direction, and this vibration of the firstdiaphragm 51 a transmits (sends) ultrasonic waves.

In transmission of such ultrasonic waves, an alternating voltage, whosefrequency is equal to the resonance frequency of the first ultrasonicelement 8 a, or is close to the resonance frequency and is smaller thanthe resonance frequency, is applied to the piezoelectric film 72 a, andthe first ultrasonic element 8 a is resonantly driven. With this, thefirst diaphragm 51 a is greatly deflected, so that ultrasonic waves canbe transmitted with high output. Preferably, in this case, the frequencyof the alternating voltage applied to the first ultrasonic element 8 ais between 0.5 times and 0.9 times with respect to the resonancefrequency of the first ultrasonic element 8 a. If the frequency of thealternating voltage is less than 0.5 times with respect to the resonancefrequency of the first ultrasonic element 8 a, the output of thetransmitted ultrasonic waves will become small and the waveform of theultrasonic waves will easily be disturbed depending on other conditions.On the other hand, if the frequency of the alternating voltage is morethan 0.9 times with respect to the resonance frequency of the firstultrasonic element 8 a, the first ultrasonic element 8 a will easily bedamaged depending on other conditions.

In receiving ultrasonic waves with the first ultrasonic element 8 a,when ultrasonic waves are input to the first diaphragm 51 a, the firstdiaphragm 51 a vibrates with respect to the film thickness direction. Inthe first ultrasonic element 8 a, this vibration of the first diaphragm51 a causes a potential difference between the surface of thepiezoelectric film 72 a on the lower electrode 71 a side and the surfaceof the piezoelectric film 72 a on the upper electrode 73 a, and areception signal (detection signal) (current) is output from the upperelectrode 73 a and the lower electrode 71 a in response to thedisplacement amount of the piezoelectric film 72 a. This signal istransmitted to the device main body 300 (see FIG. 6, FIG. 7) through thecable 210, and predetermined signal processing or the like is conductedbased on the signal. Then, in the device main body 300, an ultrasonicimage (electronic image) is formed and displayed.

In the ultrasonic probe 10, planar waves of ultrasonic waves can betransmitted in a desired direction by delaying and differentiating thetiming of transmission of ultrasonic waves from each cell unit 4arranged in parallel along the X axis direction. Here, when the area ofthe first diaphragm 51 a of the first ultrasonic element 8 a is “S1”,the area of the second diaphragm 51 b of the second ultrasonic element 8b is “S2”, and the area of the third diaphragms 51 c, 51 d of the thirdultrasonic elements 8 c, 8 d is “S3”, it is sufficient for them tosatisfy S1>S2>S3. Preferably, however, S2/S1 is within the range of 0.2to 0.8, and more preferably, S2/S1 is within the range of 0.3 to 0.6.Also, preferably, S3/S1 is within the range of 0.1 to 0.5, and morepreferably, S3/S1 is within the range of 0.2 to 0.4.

Also, when the resonance frequency of the first ultrasonic element 8 ais “F1”, the resonance frequency of the second ultrasonic element 8 b is“F2”, and the resonance frequency of the third ultrasonic elements 8 c,8 d is “F3” (F1<F2<F3), it is preferable to set S1, S2, and S3,respectively, such that F3 becomes the least common multiple of F1 andF2. The number of the second ultrasonic element 8 b of the secondultrasonic element group 3 b is greater than the number of the firstultrasonic element 8 a of the first ultrasonic element group 3 a. In thepresent embodiment, the second ultrasonic element group 3 b has three ormore second ultrasonic elements 8 b, and more specifically, the secondultrasonic element group 3 b has four second ultrasonic elements 8 b.

The numbers of the third ultrasonic elements 8 c, 8 d of the thirdultrasonic element groups 3 c, 3 d are greater than the number of thesecond ultrasonic element 8 b of the second ultrasonic element group 3b, respectively. In the present embodiment, the third ultrasonic elementgroups 3 c, 3 d have four or more third ultrasonic elements 8 c, 8 d,and more specifically, the third ultrasonic element groups 3 c, 3 d havenine third ultrasonic elements 8 c, 8 d, respectively. Here, the numberof the second ultrasonic element 8 b of the second ultrasonic elementgroup 3 b is not limited to a specific one as long as it is greater thanthe number of the first ultrasonic element 8 a of the first ultrasonicelement group 3 a. Preferably, however, the number of the secondultrasonic element 8 b of the second ultrasonic element group 3 b isbetween 4 and 6.

The numbers of the third ultrasonic elements 8 c, 8 d of the thirdultrasonic element groups 3 c, 3 d are not limited to specific ones aslong as they are greater than the number of the second ultrasonicelement 8 b of the second ultrasonic element group 3 b, respectively.Preferably, however, the numbers of the third ultrasonic elements 8 c, 8d of the third ultrasonic element groups 3 c, 3 d are between 5 to 10.When the total sum of the areas of the first diaphragms 51 a of thefirst ultrasonic element group 3 a is “A” and the total sum of the areasof the second diaphragms 51 b of the second ultrasonic element group 3 bis “B”, B/A is within the range of 0.9 to 1.1. With this configuration,since the sensitivity of the first ultrasonic element 8 a depends on thearea of the first diaphragm 51 a, the sensitivity of the firstultrasonic element group 3 a and the sensitivity of the secondultrasonic element group 3 b can be made substantially the same.Consequently, a circuit needed for matching the magnitude of a signal ina case where the sensitivity is different can be omitted, and thus thecircuit configuration can be simplified.

Preferably, B/A is within the range of 0.95 to 1.05. In this case, sincethe difference between the noise level of the first ultrasonic elementgroup 3 a and the noise level of the second ultrasonic element group 3 bis small, there is no need to conduct fine adjustment so as to compareeach signal when displaying a tomographic image. Therefore, the circuitconfiguration can further be simplified. When the total sum of the areasof the third diaphragms 51 c, 51 d of the third ultrasonic elementgroups 3 c, 3 d is “C”, C/A is within the range of 0.9 to 1.1. With thisconfiguration, the sensitivity of the first ultrasonic element group 3 aand the sensitivity of the third ultrasonic element groups 3 c, 3 d canbe made substantially the same. Consequently, a circuit needed formatching the magnitude of a signal in a case where the sensitivity isdifferent can be omitted, and thus the circuit configuration can besimplified.

Preferably, C/A is within the range of 0.95 to 1.05. In this case, sincethe difference between the noise level of the first ultrasonic elementgroup 3 a and the noise level of the third ultrasonic element group 3 cis small, there is no need to conduct fine adjustment so as to compareeach signal when displaying a tomographic image. Therefore, the circuitconfiguration can further be simplified. Also, preferably, theconducting wire for a lower electrode 711 b that is a wiring forelectrically connecting each second ultrasonic element 8 b of the secondultrasonic element group 3 b in series is provided such that the totalsum of distances Lb of the conducting wires for a lower electrode 711 bbetween two adjacent second ultrasonic elements 8 b which areelectrically connected with each other becomes shortest. With thisconfiguration, the voltage drop in the conducting wire for a lowerelectrode 711 b can be reduced.

In the present embodiment, each second ultrasonic element 8 b of thesecond ultrasonic element group 3 b is connected by the conducting wirefor a lower electrode 711 b as shown in FIG. 3. This configuration meetsthe conditions that the total sum of the distances Lb is shortest.Likewise, preferably, the conducting wire for a lower electrode 711 cthat is a wiring for electrically connecting each third ultrasonicelement 8 c of the third ultrasonic element group 3 c in series isprovided such that the total sum of distances Lc of the conducting wiresfor a lower electrode 711 c between two adjacent third ultrasonicelements 8 c which are electrically connected with each other becomesshortest. With this configuration, the voltage drop in the conductingwire for a lower electrode 711 c can be reduced.

In the present embodiment, each third ultrasonic element 8 c of thethird ultrasonic element group 3 c is connected by the conducting wirefor a lower electrode 711 c in a zigzag pattern as shown in FIG. 3. Thisconfiguration meets the conditions that the total sum of the distancesLc is shortest. Likewise, preferably, the conducting wire for a lowerelectrode 711 d that is a wiring for electrically connecting each thirdultrasonic element 8 d of the third ultrasonic element group 3 d inseries is provided such that the total sum of distances Ld of theconducting wires for a lower electrode 711 d between two adjacent thirdultrasonic elements 8 d which are electrically connected with each otherbecomes shortest. With this configuration, the voltage drop in theconducting wire for a lower electrode 711 d can be reduced.

In the present embodiment, each third ultrasonic element 8 d of thethird ultrasonic element group 3 d is connected by the conducting wirefor a lower electrode 711 d in a zigzag pattern as shown in FIG. 3. Thisconfiguration meets the conditions that the total sum of the distancesLd is shortest. Here, as the pattern of the conducting wire for a lowerelectrode 711 c, 711 d that makes the total sum of the distances Lc orLd shortest, a spiral pattern can be listed, for example, as well as theabove pattern.

Preferably, in the conducting wire for a lower electrode 711 b that is awiring for electrically connecting each second ultrasonic element 8 b ofthe second ultrasonic element group 3 b in series, all of the distancesLb of the conducting wires for a lower electrode 711 b between twoadjacent second ultrasonic elements 8 b of the second ultrasonic elementgroup 3 b which are electrically connected with each other are the same.With this configuration, the phase difference of ultrasonic wavesbetween two adjacent second ultrasonic elements 8 b which areelectrically connected with each other can be made the same in thesecond ultrasonic element group 3 b, and thus designing can be conductedeasily.

Likewise, preferably, in the conducting wire for a lower electrode 711 cthat is a wiring for electrically connecting each third ultrasonicelement 8 c of the third ultrasonic element group 3 c in series, all ofthe distances Lc of the conducting wires for a lower electrode 711 cbetween two adjacent third ultrasonic elements 8 c of the thirdultrasonic element group 3 c which are electrically connected with eachother are the same. With this configuration, the phase difference ofultrasonic waves between two adjacent third ultrasonic elements 8 cwhich are electrically connected with each other can be made the same inthe third ultrasonic element group 3 c, and thus designing can beconducted easily.

Likewise, preferably, in the conducting wire for a lower electrode 711 dthat is a wiring for electrically connecting each third ultrasonicelement 8 d of the third ultrasonic element group 3 d in series, all ofthe distances Ld of the conducting wires for a lower electrode 711 dbetween two adjacent third ultrasonic elements 8 d of the thirdultrasonic element group 3 d which are electrically connected with eachother are the same. With this configuration, the phase difference ofultrasonic waves between two adjacent third ultrasonic elements 8 dwhich are electrically connected with each other can be made the same inthe third ultrasonic element group 3 d, and thus designing can beconducted easily.

Also, preferably, the distance Lc and the distance Ld are the same. Withthis configuration, the phase difference of ultrasonic waves between twoadjacent third ultrasonic elements 8 c of the third ultrasonic elementgroup 3 c which are electrically connected with each other and the phasedifference of ultrasonic waves between two adjacent third ultrasonicelements 8 d of the third ultrasonic element group 3 d which areelectrically connected with each other can be made the same. Therefore,designing can be conducted easily.

Also, preferably, the distance Lb, the distance Lc, and the distance Ldare the same. With this configuration, the phase difference ofultrasonic waves between two adjacent second ultrasonic elements 8 b ofthe second ultrasonic element group 3 b which are electrically connectedwith each other, the phase difference of ultrasonic waves between twoadjacent third ultrasonic elements 8 c of the third ultrasonic elementgroup 3 c which are electrically connected with each other, and thephase difference of ultrasonic waves between two adjacent thirdultrasonic elements 8 d of the third ultrasonic element group 3 d whichare electrically connected with each other can be made the same.Therefore, designing can be conducted easily. Here, the above-describedexpression that “distances are the same” includes a case where thedistances are almost the same and a case where the distances aresubstantially the same as well as a case where the distances arecompletely the same.

Next, explanations will be made on a usage example of a case where theultrasonic probe 10 is applied to the diagnostic device 100 describedbelow. In this case, the third ultrasonic element group 3 d is not used.In transmission of ultrasonic waves, any one of the first ultrasonicelement group 3 a, the second ultrasonic element group 3 b, and thethird ultrasonic element group 3 c is selected and used. In reception ofultrasonic waves, any one of the first ultrasonic element group 3 a, thesecond ultrasonic element group 3 b, and the third ultrasonic elementgroup 3 c is selected and used. As a display mode, either one of a B(brightness) mode and a harmonic mode is used. Such a case will beexplained. However, the third ultrasonic element group 3 d may be usedinstead of the third ultrasonic element group 3 c. Further, both of thethird ultrasonic element group 3 c and the third ultrasonic elementgroup 3 d may be used. The B mode is a display mode which displays animage by changing the intensity of the received ultrasonic waves intobrightness (by conducting brightness modulation).

When ultrasonic waves propagate through a living body, the waveform isdeformed due to the difference in speed of the ultrasonic wavespropagating the living body, which causes high harmonic components withrespect to the transmitted ultrasonic waves. The harmonic mode is adisplay mode which displays an image by receiving the high harmoniccomponents with respect to the transmitted ultrasonic waves. Normally,in the harmonic mode, second harmonic waves, having frequency of twiceas much as fundamental waves which are ultrasonic waves to betransmitted or third harmonic waves having frequency of three times, arereceived. In a case of diagnosing a part of a long distance, theharmonic mode is not used because high harmonic waves are hardlygenerated. In the harmonic mode, since high harmonic waves are received,the sensitivity can be improved and good ultrasonic images can beobtained.

The resonance frequency of the first ultrasonic element group 3 a is1.00 MHz, the resonance frequency of the second ultrasonic element group3 b is 1.50 MHz, and the resonance frequencies of the third ultrasonicelement groups 3 c and 3 d are 3.00 MHz, respectively. Incidentally, 0.5times-0.9 times of the resonance frequency of the first ultrasonicelement group 3 a is 0.50 MHz-0.90 MHz. 0.5 times-0.9 times of theresonance frequency of the second ultrasonic element group 3 b is 0.75MHz-1.35 MHz. 0.5 times-0.9 times of the resonance frequencies of thethird ultrasonic element groups 3 c and 3 d are 1.5 MHz-2.70 MHz,respectively.

In the following explanations, a long distance refers to a distance thatis more than 200 mm and equal to or less than 300 mm. A middle distancerefers to a distance that is more than 50 mm and equal to or less than200 mm. A short distance refers to a distance that is equal to or lessthan 50 mm. In the ultrasonic probe 10, ultrasonic waves can betransmitted and received at various frequencies by changing thecombination of the ultrasonic element group that transmits ultrasonicwaves and the ultrasonic element group that receives ultrasonic waves,and thus various ultrasonic images can be obtained by using ultrasonicwaves of various frequencies. Therefore, the same ultrasonic probe 10can be used for diagnosis of parts of a short distance, a middledistance, and a long distance, respectively, without replacing theultrasonic probe 10. Accordingly, a laborious process to an operator canbe reduced.

When a part of a short distance is diagnosed, ultrasonic waves aretransmitted by the third ultrasonic element group 3 c that can generateultrasonic waves of high frequency, and ultrasonic waves are received bythe same third ultrasonic element group 3 c, for example. Consequently,the resolution can be improved, and a good image of a part of a shortdistance can be obtained. Further, when a part of a long distance isdiagnosed, ultrasonic waves are transmitted by the first ultrasonicelement group 3 a or the second ultrasonic element group 3 b, andultrasonic waves are received by the first ultrasonic element group 3 a,the second ultrasonic element group 3 b, or the third ultrasonic elementgroup 3 c, for example. Consequently, a good image of a part of a longdistance can be obtained. Further, when the harmonic mode is used, andultrasonic waves are received by the second ultrasonic element group 3 bor the third ultrasonic element group 3 c, for example, a good image ofa part of a middle distance or a long distance can be obtained. Next,specific examples will be explained based on Table 1 shown below.

TABLE 1 Trans- Trans- Recep- mitting Receiving mission tion ultrasonicultrasonic fre- fre- element element quency quency group group ModeRange (MHz) (MHz) Config- 3a 3a B mode Long 0.60 0.60 uration distance 1Config- 3a 3a B mode Long 0.75 0.75 uration distance 2 Config- 3a 3a Bmode Middle 0.90 0.90 uration distance 3 Config- 3a 3b Harmonic Long0.60 1.20 uration distance 4 Config- 3a 3b Harmonic Middle 0.75 1.50uration distance 5 Config- 3a 3c Harmonic Long 0.60 1.80 urationdistance 6 Config- 3b 3b B mode Middle 0.90 0.90 uration distance 7Config- 3b 3a B mode Middle 0.90 0.90 uration distance 8 Config- 3b 3b Bmode Middle 1.20 1.20 uration distance 9 Config- 3b 3b B mode Middle1.35 1.35 uration distance 10 Config- 3b 3c Harmonic Long 1.20 2.40uration distance 11 Config- 3b 3c Harmonic Long 1.35 2.70 urationdistance 12 Config- 3b 3c Harmonic Long 1.00 3.00 uration distance 13Config- 3c 3c B mode Short 1.80 1.80 uration distance 14 Config- 3c 3c Bmode Short 2.40 2.40 uration distance 15 Config- 3c 3c B mode Short 2.702.70 uration distance 16

As shown in Table 1, in Configuration 1, the B mode is used, ultrasonicwaves are transmitted by the first ultrasonic element group 3 a, andultrasonic waves are received by the first ultrasonic element group 3 a.This configuration is used for diagnosis of a part of a long distance.The frequency of the transmitted ultrasonic waves is 0.60 MHz, forexample, and the frequency of the received ultrasonic waves is 0.60 MHz,for example. In Configuration 2, the B mode is used, ultrasonic wavesare transmitted by the first ultrasonic element group 3 a, andultrasonic waves are received by the first ultrasonic element group 3 a.This configuration is used for diagnosis of a part of a long distance.The frequency of the transmitted ultrasonic waves is 0.75 MHz, forexample, and the frequency of the received ultrasonic waves is 0.75 MHz,for example.

In Configuration 3, the B mode is used, ultrasonic waves are transmittedby the first ultrasonic element group 3 a, and ultrasonic waves arereceived by the first ultrasonic element group 3 a. This configurationis used for diagnosis of a part of a middle distance. The frequency ofthe transmitted ultrasonic waves is 0.90 MHz, for example, and thefrequency of the received ultrasonic waves is 0.90 MHz, for example. InConfiguration 4, the harmonic mode is used, ultrasonic waves aretransmitted by the first ultrasonic element group 3 a, and ultrasonicwaves are received by the second ultrasonic element group 3 b. Thisconfiguration is used for diagnosis of a part of a long distance. Thefrequency of the transmitted ultrasonic waves is 0.60 MHz, for example,and the frequency of the received ultrasonic waves is 1.20 MHz, forexample.

In Configuration 5, the harmonic mode is used, ultrasonic waves aretransmitted by the first ultrasonic element group 3 a, and ultrasonicwaves are received by the second ultrasonic element group 3 b. Thisconfiguration is used for diagnosis of a part of a middle distance. Thefrequency of the transmitted ultrasonic waves is 0.75 MHz, for example,and the frequency of the received ultrasonic waves is 1.50 MHz, forexample. In Configuration 6, the harmonic mode is used, ultrasonic wavesare transmitted by the first ultrasonic element group 3 a, andultrasonic waves are received by the third ultrasonic element group 3 c.This configuration is used for diagnosis of a part of a long distance.The frequency of the transmitted ultrasonic waves is 0.60 MHz, forexample, and the frequency of the received ultrasonic waves is 1.80 MHz,for example.

In Configuration 7, the B mode is used, ultrasonic waves are transmittedby the second ultrasonic element group 3 b, and ultrasonic waves arereceived by the second ultrasonic element group 3 b. This configurationis used for diagnosis of a part of a middle distance. The frequency ofthe transmitted ultrasonic waves is 0.90 MHz, for example, and thefrequency of the received ultrasonic waves is 0.90 MHz, for example. InConfiguration 8, the B mode is used, ultrasonic waves are transmitted bythe second ultrasonic element group 3 b, and ultrasonic waves arereceived by the first ultrasonic element group 3 a. This configurationis used for diagnosis of a part of a middle distance. The frequency ofthe transmitted ultrasonic waves is 0.90 MHz, for example, and thefrequency of the received ultrasonic waves is 0.90 MHz, for example.

In Configuration 9, the B mode is used, ultrasonic waves are transmittedby the second ultrasonic element group 3 b, and ultrasonic waves arereceived by the second ultrasonic element group 3 b. This configurationis used for diagnosis of a part of a middle distance. The frequency ofthe transmitted ultrasonic waves is 1.20 MHz, for example, and thefrequency of the received ultrasonic waves is 1.20 MHz, for example. InConfiguration 10, the B mode is used, ultrasonic waves are transmittedby the second ultrasonic element group 3 b, and ultrasonic waves arereceived by the second ultrasonic element group 3 b. This configurationis used for diagnosis of a part of a middle distance. The frequency ofthe transmitted ultrasonic waves is 1.35 MHz, for example, and thefrequency of the received ultrasonic waves is 1.35 MHz, for example.

In Configuration 11, the harmonic mode is used, ultrasonic waves aretransmitted by the second ultrasonic element group 3 b, and ultrasonicwaves are received by the third ultrasonic element group 3 c. Thisconfiguration is used for diagnosis of a part of a long distance. Thefrequency of the transmitted ultrasonic waves is 1.20 MHz, for example,and the frequency of the received ultrasonic waves is 2.40 MHz, forexample. In Configuration 12, the harmonic mode is used, ultrasonicwaves are transmitted by the second ultrasonic element group 3 b, andultrasonic waves are received by the third ultrasonic element group 3 c.This configuration is used for diagnosis of a part of a long distance.The frequency of the transmitted ultrasonic waves is 1.35 MHz, forexample, and the frequency of the received ultrasonic waves is 2.70 MHz,for example.

In Configuration 13, the harmonic mode is used, ultrasonic waves aretransmitted by the second ultrasonic element group 3 b, and ultrasonicwaves are received by the third ultrasonic element group 3 c. Thisconfiguration is used for diagnosis of a part of a long distance. Thefrequency of the transmitted ultrasonic waves is 1.00 MHz, for example,and the frequency of the received ultrasonic waves is 3.00 MHz, forexample. In Configuration 14, the B mode is used, ultrasonic waves aretransmitted by the third ultrasonic element group 3 c, and ultrasonicwaves are received by the third ultrasonic element group 3 c. Thisconfiguration is used for diagnosis of a part of a short distance. Thefrequency of the transmitted ultrasonic waves is 1.80 MHz, for example,and the frequency of the received ultrasonic waves is 1.80 MHz, forexample.

In Configuration 15, the B mode is used, ultrasonic waves aretransmitted by the third ultrasonic element group 3 c, and ultrasonicwaves are received by the third ultrasonic element group 3 c. Thisconfiguration is used for diagnosis of a part of a short distance. Thefrequency of the transmitted ultrasonic waves is 2.40 MHz, for example,and the frequency of the received ultrasonic waves is 2.40 MHz, forexample. In Configuration 16, the B mode is used, ultrasonic waves aretransmitted by the third ultrasonic element group 3 c, and ultrasonicwaves are received by the third ultrasonic element group 3 c. Thisconfiguration is used for diagnosis of a part of a short distance. Thefrequency of the transmitted ultrasonic waves is 2.70 MHz, for example,and the frequency of the received ultrasonic waves is 2.70 MHz, forexample.

In the above examples, any one of the first ultrasonic element group 3a, the second ultrasonic element group 3 b, and the third ultrasonicelement group 3 c is selected and used for transmission of ultrasonicwaves, and any one of the first ultrasonic element group 3 a, the secondultrasonic element group 3 b, and the third ultrasonic element group 3 cis selected and used for reception of ultrasonic waves. However, theinvention is not limited to these examples. Any two of the firstultrasonic element group 3 a, the second ultrasonic element group 3 b,and the third ultrasonic element group 3 c may be selected and used, orall of them may be used, for transmission of ultrasonic waves. Also, anytwo of the first ultrasonic element group 3 a, the second ultrasonicelement group 3 b, and the third ultrasonic element group 3 c may beselected and used, or all of them may be used, for reception ofultrasonic waves.

Modification Example of Ultrasonic Transducer

In the ultrasonic transducer 1 according to the above-describedembodiment, the number of the first ultrasonic element 8 a of the firstultrasonic element group 3 a is one. However, the number may be two, ormay be three or more. Here, explanations will be made on a case wherethe number of the first ultrasonic element 8 a of the first ultrasonicelement group 3 a is three or more in the ultrasonic transducer 1.

Preferably, the conducting wire for a lower electrode 711 a that is awiring for electrically connecting each first ultrasonic element 8 a ofthe first ultrasonic element group 3 a in series is provided such thatthe total sum of distances of the conducting wires for a lower electrode711 a between two adjacent first ultrasonic elements 8 a which areelectrically connected with each other becomes shortest. With thisconfiguration, the voltage drop in the conducting wire for a lowerelectrode 711 a can be reduced.

Preferably, in the conducting wire for a lower electrode 711 a that is awiring for electrically connecting each first ultrasonic element 8 a ofthe first ultrasonic element group 3 a in series, all of the distancesof the conducting wires for a lower electrode 711 a between two adjacentfirst ultrasonic elements 8 a of the first ultrasonic element group 3 awhich are electrically connected with each other are the same. With thisconfiguration, the phase difference of ultrasonic waves between twoadjacent first ultrasonic elements 8 a which are electrically connectedwith each other can be made the same in the first ultrasonic elementgroup 3 a, and thus designing can be conducted easily.

Also, preferably, the distance of the conducting wire for a lowerelectrode 711 a between two adjacent first ultrasonic elements 8 a ofthe first ultrasonic element group 3 a which are electrically connectedwith each other, the distance Lb, the distance Lc, and the distance Ldare the same. With this configuration, the phase difference ofultrasonic waves between two adjacent first ultrasonic elements 8 a ofthe first ultrasonic element group 3 a which are electrically connectedwith each other, the phase difference of ultrasonic waves between twoadjacent second ultrasonic elements 8 b of the second ultrasonic elementgroup 3 b which are electrically connected with each other, the phasedifference of ultrasonic waves between two adjacent third ultrasonicelements 8 c of the third ultrasonic element group 3 c which areelectrically connected with each other, and the phase difference ofultrasonic waves between two adjacent third ultrasonic elements 8 d ofthe third ultrasonic element group 3 d which are electrically connectedwith each other can be made the same. Therefore, designing can beconducted easily. The ultrasonic probe 10 and the ultrasonic transducer1 described above can be applied to various kinds of electronicinstruments such as diagnostic devices in a preferred manner.Hereinafter, an embodiment of a diagnostic device will be explained as arepresentative of an embodiment of an electronic instrument.

Embodiment of Diagnostic Device (Electronic Instrument)

FIG. 6 is a perspective view showing an embodiment of the diagnosticdevice according to the invention. FIG. 7 is a block diagram showing theembodiment of the diagnostic device according to the invention. As shownin FIG. 6 and FIG. 7, the diagnostic device 100 has the above-describedultrasonic probe 10, and the device main body 300 which is electricallyconnected with the ultrasonic probe 10 through the cable 210.

The device main body 300 has a control section (control means) 310, adrive signal generating section 320, a detection signal processingsection 330, an image signal processing section 340, and an imagedisplay section (display means) 350. The signal processing section isconstructed of the detection signal processing section 330 and the imagesignal processing section 340. The control section 310 is constructed ofa microcomputer and the like, for example, and controls the entiredevice main body 300 such as the drive signal generating section 320 andthe image signal processing section 340. The image display section 350is constructed of a display device such as a CRT or an LCD, for example.

Next, the operation of the diagnostic device 100 will be explained. Inconducting a test, the surface of the acoustic matching section 6 of theultrasonic probe 10 is applied to a living body as a test target, andthe diagnostic device 100 is activated. First, the control section 310outputs a transmission order to the drive signal generating section 320,the drive signal generating section 320 transmits a drive signal fordriving each ultrasonic element 8 to the ultrasonic element 8 at apredetermined timing. In this manner, each of the ultrasonic elements 8is driven at a predetermined timing. Then, ultrasonic waves aretransmitted from the ultrasonic transducer 1 of the ultrasonic probe 10.

The transmitted ultrasonic waves propagate through a living body, andthe ultrasonic waves reflected on a predetermined part of the livingbody are input to the ultrasonic transducer 1 of the ultrasonic probe10. Then, a detection signal corresponding to the input ultrasonic wavesare output from the ultrasonic transducer 1. The detection signal istransmitted to the detection signal processing section 330 of the devicemain body 300 through the cable 210. The detection signal undergoespredetermined signal processing in the detection signal processingsection 330, and is converted into a digital signal by an A/D converterincluded in the detection signal processing section 330. The A/Dconverter is not shown in the drawing.

The digital signal output from the detection signal processing section330 is input to the image signal processing section 340, and issequentially stored in a primary storing section included in the imagesignal processing section 340 as areal data in synchronization with aframe timing signal. The primary storing section is not shown in thedrawing. The image signal processing section 340 reconstructstwo-dimensional or three-dimensional image data based on each arealdata, and also conducts image processing such as interpolation, responseemphasis processing, or tone processing to the image data. The imagedata, to which image processing has been conducted, is stored in asecondary storing section included in the image signal processingsection 340. The secondary storing section is not shown in the drawing.

The image data, to which image processing has been conducted, is thenread out from the secondary storing section of the image signalprocessing section 340 and is input to the image display section 350.The image display section 350 displays an image based on the image data.A medical service worker such as a doctor conducts diagnosis or the likeby observing an image displayed on the image display section 350. Theinvention is not limited to the ultrasonic transducer, the ultrasonicprobe, the diagnostic device, and the electronic instrument of theinvention explained in the above based on the embodiment shown in thedrawing. The configuration of each section can be replaced with anyconfiguration that has a similar function. Also, another optionalelement may be added to the invention.

In the above-described embodiment, the cell unit is arrangedtwo-dimensionally. However, the invention is not limited to this, andthe cell unit can be arranged one-dimensionally, for example. Further,in the above-described embodiment, the cell units are plural. However,the invention is not limited to this, and the cell unit may be single.Further, in the above-described embodiment, the cell unit has threekinds (three sizes) of ultrasonic element groups in which the areas ofthe diaphragms are different. However, the invention is not limited tothis, and the cell unit may have two kinds (two sizes) of ultrasonicelement groups in which the areas of the diaphragms are different, ormay have four or more kinds (four or more sizes) of ultrasonic elementgroups in which the areas of the diaphragms are different.

In the above-described embodiment, the ultrasonic element of the firstultrasonic element group is single. However, the invention is notlimited to this, and a plurality of ultrasonic elements may be providedin the first ultrasonic element group. In such a case, the firstultrasonic elements of the first ultrasonic element group areelectrically connected in series. Further, according to the invention,the ultrasonic transducer (the ultrasonic probe) is not limited to acontact type sensor that is used by being brought into contact with atest target, and can be applied to a non-contact type sensor such as aproximity sensor that is used without being brought into contact with atest target.

According to one aspect of the embodiment, an ultrasonic transducer ofthe embodiment includes “m” first ultrasonic elements and “n” secondultrasonic elements. The “m” first ultrasonic elements includes firstdiaphragms. The “m” first ultrasonic elements are configured andarranged to transmit and receive ultrasonic waves, where “m” representsa number of the first ultrasonic elements and is an integer of 1 ormore. Each of the first diaphragms having a first area. The “n” secondultrasonic elements include second diaphragms. Each of the “n” seconddiaphragms has a second area being smaller than the first area. The “n”second ultrasonic elements are configured and arranged to transmit andreceive the ultrasonic waves, where “n” represents a number of thesecond ultrasonic elements and is an integer larger than “m”. The “m”first ultrasonic elements are electrically connected in series in a casewhere “m” is an integer of 2 or more. The “n” second ultrasonic elementsare electrically connected in series. B/A is within a range of 0.9 to1.1, when a total sum of the first areas is “A” and a total sum of thesecond areas is “B”.

According to another aspect of the embodiment, an ultrasonic transducerincludes a plurality of ultrasonic elements being arranged on theultrasonic transducer with predetermined intervals. The plurality ofultrasonic elements include “m” first ultrasonic elements and “n” secondultrasonic elements. The “m” first ultrasonic elements include firstdiaphragms. The “m” first ultrasonic elements are configured andarranged to transmit and receive ultrasonic waves, where “m” representsthe number of the first ultrasonic elements and is an integer of 1 ormore. Each of the first diaphragms has a first area. The “n” secondultrasonic elements include second diaphragms. Each of the “n” seconddiaphragms has a second area being smaller than the first area. The “n”second ultrasonic elements are configured and arranged to transmit andreceive the ultrasonic waves, where “n” representing the number of thesecond ultrasonic elements and is an integer larger than “m”. The “m”first ultrasonic elements are electrically connected in series in a casewhere “m” is an integer of 2 or more. The “n” second ultrasonic elementsare electrically connected in series. B/A is within a range of 0.9 to1.1, when a total sum of the first areas is “A” and a total sum of thesecond areas is “B”.

According to another aspect of the embodiment, an ultrasonic transducerincludes a substrate, a supporting film, and a piezoelectric body. Thesubstrate includes a plurality of openings. The supporting film isconfigured to cover the plurality of openings. The piezoelectric body isconfigured on the supporting film at one of the plurality of openings.The plurality of openings include “m” first openings, where “m”represents a number of the first openings and is an integer of 1 ormore. Each of the first openings has a first opening area covered withthe supporting film on a surface of the substrate. The plurality ofopenings include “n” second openings, where “n” represents a number ofthe second openings and is an integer larger than “m”. Each of thesecond openings has a second opening area that is smaller than the firstarea. “m” first piezoelectric bodies, which are formed corresponding tothe “m” first openings, of the piezoelectric body are electricallyconnected in series in a case where “m” is an integer of 2 or more. “n”second piezoelectric bodies, which are formed corresponding to the “n”second openings, of the piezoelectric body are electrically connected inseries. B/A is within the range of 0.9 to 1.1, when a total sum of thefirst opening areas is “A” and a total sum of the second opening areasis “B”.

According to another aspect of the embodiment, an ultrasonic transducerincludes a substrate, a supporting film, and a piezoelectric body. Thesubstrate includes a plurality of openings. The supporting film isconfigured to cover the plurality of openings. The piezoelectric body isconfigured on the supporting film at one of the plurality of openings.The plurality of openings include an arrangement opening group withpredetermined intervals. The opening group include “m” first openings,where “m” represents a number of the first openings and is an integer of1 or more. Each of the “m” first openings has a first opening areacovered with the supporting film on a surface of the substrate. Theopening group includes “n” second openings, where “n” represents anumber of the second openings and is an integer larger than “m”. Each ofthe “m” second openings has a second opening area that is smaller thanthe first area. “m” first piezoelectric bodies, which are formedcorresponding to the “m” first openings, of the piezoelectric body areelectrically connected in series in a case where “m” is an integer of 2or more. “n” second piezoelectric bodies, which are formed correspondingto the “n” second openings, of the piezoelectric body are electricallyconnected in series. B/A is within the range of 0.9 to 1.1, when a totalsum of the first areas is “A” and a total sum of the second areas is “B”

General Interpretation of Terms

In understanding the scope of the present invention, the term“comprising” and its derivatives, as used herein, are intended to beopen ended terms that specify the presence of the stated features,elements, components, groups, integers, and/or steps, but do not excludethe presence of other unstated features, elements, components, groups,integers and/or steps. The foregoing also applies to words havingsimilar meanings such as the terms, “including”, “having” and theirderivatives. Also, the terms “part,” “section,” “portion,” “member” or“element” when used in the singular can have the dual meaning of asingle part or a plurality of parts. Finally, terms of degree such as“substantially”, “about” and “approximately” as used herein mean areasonable amount of deviation of the modified term such that the endresult is not significantly changed. For example, these terms can beconstrued as including a deviation of at least ±5% of the modified termif this deviation would not negate the meaning of the word it modifies.

While only selected embodiments have been chosen to illustrate thepresent invention, it will be apparent to those skilled in the art fromthis disclosure that various changes and modifications can be madeherein without departing from the scope of the invention as defined inthe appended claims. Furthermore, the foregoing descriptions of theembodiments according to the present invention are provided forillustration only, and not for the purpose of limiting the invention asdefined by the appended claims and their equivalents.

What is claimed is:
 1. An ultrasonic transducer comprising: “m” firstultrasonic elements including first diaphragms, the “m” first ultrasonicelements being configured and arranged to transmit and receiveultrasonic waves, where “m” represents a number of the first ultrasonicelements and is an integer of 1 or more, each of the first diaphragmshaving a first area and a piezoelectric body that is disposed on thefirst area; and “n” second ultrasonic elements including seconddiaphragms, each of the “n” second diaphragms having a second area and apiezoelectric body that is disposed on the second area, the second areabeing smaller than the first area, the “n” second ultrasonic elementsbeing configured and arranged to transmit and receive the ultrasonicwaves, where “n” represents a number of the second ultrasonic elementsand is an integer larger than “m”, the “m” first ultrasonic elementsbeing electrically connected in series by a first electric connection ina case where “m” is an integer of 2 or more, the “n” second ultrasonicelements being electrically connected in series by a second electricconnection, the second electric connection being electricallydisconnected from the first electric connection, B/A being within arange of 0.9 to 1.1, when a total sum of the first areas is “A” and atotal sum of the second areas is “B”.
 2. The ultrasonic transduceraccording to claim 1, wherein “n” is an integer of 3 or more, and inwiring to connect electrically each of the “n” second ultrasonicelements in series, a distance between two adjacent second ultrasonicelements among the “n” second ultrasonic elements is the same.
 3. Theultrasonic transducer according to claim 1, wherein “m” is an integer of3 or more, “n” is an integer of 4 or more, and in wiring to connectelectrically each of the “m” first ultrasonic elements in series, adistance between two adjacent first ultrasonic elements among the “m”first ultrasonic elements is the same.
 4. The ultrasonic transduceraccording to claim 3, wherein “k” is an integer of 4 or more, and inwiring to connect electrically the “k” third ultrasonic elements inseries, a distance between two adjacent third ultrasonic elements amongthe “k” third ultrasonic elements is the same.
 5. The ultrasonictransducer according to claim 1 further comprising “k” third ultrasonicelements including third diaphragms, each of the “k” third diaphragmshaving a third area being smaller than the second area, the “k” thirdultrasonic elements being configured and arranged to transmit andreceive the ultrasonic waves, where “k” represents a number of the thirdultrasonic elements and is an integer larger than “m”, wherein the “k”third ultrasonic elements are electrically connected in series, and C/Ais within the range of 0.9 to 1.1, when a total sum of the third areasis “C”.
 6. The ultrasonic transducer according to claim 5, wherein “m”is an integer of 3 or more, “n” is an integer of 4 or more, “k” is aninteger of 5 or more, and all of the distance between two adjacent firstultrasonic elements among the “m” first ultrasonic elements, thedistance between two adjacent second ultrasonic among the “n” secondultrasonic elements, and the distance between two adjacent thirdultrasonic elements among the “k” third ultrasonic elements are thesame.
 7. An ultrasonic transducer comprising: a plurality of ultrasonicelements being arranged on the ultrasonic transducer with predeterminedintervals, the plurality of ultrasonic elements including “m” firstultrasonic elements including first diaphragms, the “m” first ultrasonicelements being configured and arranged to transmit and receiveultrasonic waves, where “m” representing the number of the firstultrasonic elements and is an integer of 1 or more, each of the firstdiaphragms having a first area and a piezoelectric body that is disposedon the first area, and “n” second ultrasonic elements including seconddiaphragms, each of the “n” second diaphragms having a second area and apiezoelectric body that is disposed on the second area, the second areabeing smaller than the first area, the “n” second ultrasonic elementsbeing configured and arranged to transmit and receive the ultrasonicwaves, where “n” representing the number of the second ultrasonicelements and is an integer larger than “m”, the “m” first ultrasonicelements being electrically connected in series by a first electricconnection in a case where “m” is an integer of 2 or more, the “n”second ultrasonic elements being electrically connected in series by asecond electric connection, the second electric connection beingelectrically disconnected from the first electric connection, B/A beingwithin a range of 0.9 to 1.1, when a total sum of the first areas is “A”and a total sum of the second areas is “B”.
 8. A probe comprising: theultrasonic transducer according to claim 1; and a case in which theultrasonic transducer is accommodated.
 9. A diagnostic devicecomprising: the ultrasonic transducer according to claim 1; a case inwhich the ultrasonic transducer is accommodated; and a device main bodythat is provided with a microcomputer configured to conduct a signalprocessing based on a signal output from the ultrasonic transducer. 10.An electronic instrument comprising: the ultrasonic transducer accordingto claim 1; a case in which the ultrasonic transducer is accommodated;and a device main body that is provided with a microcomputer configuredto conduct a signal processing based on a signal output from theultrasonic transducer.